Stabilized circuit for electrical relay fuze



Sept. 26, 1961 H. E. RUEHLEMANN 3,001,477

STABILIZED CIRCUIT FOR ELECTRICAL RELAY FUZE Filed Feb. 6, 1956 FIGJ.

L 2 L I 2 22 TO SOURCE 2 36 T0 SOURCE C 0F TRIGGER 3 TI PULSE 1 wxl INVENTOR I? H. E. RUEHLEMANN ATTORNEY I going disadvantages.

States atentffice 3,001,477. Patented Sept. 26., 1961 The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to an electrical fuze for an ordnance device which is triggered by a small electrical signal resulting from environmental conditions such, for example, as radio waves, static fields, magnetic fields, radiation, sound, vibration or the like. More specifically, the invention relates to a fuze for a weapon fired by the discharge of a condenser in response to a breakdown voltage of the diode of the fuze in which the voltage applied to the diode prior to the firing thereof is maintained at a few millivolts below the breakdown voltage of the diode whereby signals of low order of magnitude are suflicient to fire the diodes when applied thereto.

In devices of this type heretofore devised it has been the usual practice to employ a final voltage at the terminals of the condenser in the order of several volts below the breakdown voltage of the diode by reason of the instability in breakdown voltage of different diodes presently available for use with such a fuze. Under these conditions it has been found necessary to employ a trigger signal of several volts to raise the voltage of the diode to a breakdown value sufficient to fire the tube.

In the device of the instant invention, this ditference of breakdown voltage for diiferent diodes is automatically compensated for by the novel circuit and arrangement of the components thereof as will more clearly appear as the description proceeds. In certain other prior art devices it has been the usual practice. to switch the diode after stabilization from the stabilization circuit to the ignition circuit for the reason that the stabilization circuit is of necessity a high impedance circuit whereas the ignition circuit is of low impedance in orderto allow ignition of the electrical primer in response to the discharge current of the condenser as the diode is triggered. Under certain conditions of service this switching operation has been found to be undesirable and in some cases impossible, particularly when employed'with certain types of electrical fuzes in ordnance applications.

The device of the present invention possesses all of the advantages of the prior are devices and none of the fore- In accordance with the preferred embodiment of the invention the stabilization device is continuously connected to the diode and the electrical primer is switched in parallel connection with the stabilization elements after the stabilization operation has been completed. The voltage across the diodes at this time is at a value of only a few millivolts less than the breakdown voltage of the diode and the fuze, therefore, is triggered by a small incremental voltage signal suflicient ,to cause the diode to break down and fire the electric primer by the discharge current of a condenser connected thereto.

Means are also provided for firing the primer in the event that a firing impulse is not received within a predetermined period of time after the fuze is armed.

. One of the objects of the present invention is the provision of an electrical fuze in which new and improved means are provided for connecting a low impedance elech tric primer to a firing circuit without disconnecting the high impedance stabilization circuit therefrom.

7 another object is the provision of new and improved means for adjusting the voltage of the stabilization condense; to "a value slightly less than the breakdown voltage of a diodeassociated therewith.

Still another object is the provision of a-new and improved circuit for a bomb fuze in which new and improved means 'are' provided far controlling the stabilization of avibrationally operated, diode armed at impact and in which means are provided for firing the primer by condenser discharge through the vibrational tube" a V predetermined time after, impact.

furtherobje'ct is to provide an electrical. proximity fuze having new and improved means for rocket arming, point detonation, and self-destruction Within aselec'table period of time after arming.

Other objects and many of the attendant advantages ofthis invention will'be readily appreciated as'the' same becomesb'ette'r understood by reference to the following i as a firing impulseof is applied thereto;

"detailed description when considered in 20 I connection with the accompanying drawings wherein: i

. FIG. 1 is a circuit for firing an electroresponsive detonator by discharge of apa'ir ofv serially connected'diodes a small fractional portion ofa volt FIG. 2 is a circuit for a bomb fuze armed at impact in which the stabilizing and firing circuits include a vibration operated diode and in'which the electric primer is fired by'a condenser discharge through the vibration diode and a second diode in series therewith when the c arge on the condenser has built .up to a predetermined vaiirejand f a FIG; 3 is circuit suitable for use with a proximity fuze with rocket features V 1 Referring now to the drawing for a more complete understanding'of the invention and more particularly to FIG. 1 thereof on which isshown a circuit for use with an electrical fuze in which ahigh impedancestabilization device is continuously connected to a firingc'ondenser in v l c series with sp n of diodes for stabilizingthevoltage of the condenser to a value slightly less thesum of the breakdown voltages of the two diodes and in 'whichthe electroresponsive detonator is connected across the stabilii zation device in parallel relationtherewith when the volt- ,minal 10 then adapted for connection to a source of age of the condenser has been stabilized. 7

More specifically, the circuit comprises an input ter- DC. potential E, the connection from the potential source andto ground; 1Anfel ectroresponsive detonator 17 is iconnectedas shown to ground andvto a switchar'm ltl ret with a grounded terminal 19 and movable to a terminal being completed at terminal 11. Terminal 11, it willbe noted, is preferably grounded as shown. Terminal 1G is connected by switch 12 to conductor 13, the circuit being continued to one'terminai of condenser C1, the opposite terminal of which is grounded. Conductor 13 isalso connected to condenser C2 and thence by of wayof I switch to ground. The capacity of condenser C2 is but a smallfra'ctional portion of the capacity of condenser Cl and when connected thereacross by the operation of switch 14- condenser C2 receives a small fracterminal of diode T1, the opposite terminal 'of diode T1 being connected to a stabilization device indicated generally by the numeral 16, the opposi tfe terminal' of which is continuously connecte'd'to one terminal of condenser. C1

spectively, the switch arm being normally in engagement s t lrl t il a ivs h s 1 l l 'it v sf i 'self destruction and pointdetonating detonator is connected to the firing circuit in parallel with the stabilization device.

Conductor 15 is connected as by condenser 22 to a firing mechanism (not shown) responsive to a predetermined environmental condition such, for example, as radio waves, a static field, magnetic field, radiation, sound, vibration or the like. The specific field sensing mechanism forms no part of the present invention, it being merely necessary that a firing impulse of the order of a few millivolts only is required to be applied to the condenser 22 in response to the sensing of the predetermined environmental condition thereby.

The operation of the circuit of FIG. 1 will now be described. Let it be assumed, by way of example, that the switch 12 is closed and that a voltage E is applied to terminals and 11 and that the switches 14 and 18 are in the position shown on the drawing. The conductor 13 is now disconnected from the voltage source E as for example by opening switch 12 and the voltage on condenser C1 at this time is the voltage of the source E. The voltage E, it will be noted, is greater than the breakdown voltage of tubes T1 and T2 and these tubes, therefore, fire over a circuit including the resistor of the stabilization device 16. The condenser of stabilization device 16 is now charged to a value of voltage such that the voltage across diodes T1 and T2 is reduced to a value insufiicient to maintain ionization of the tubes and tubes T1 and T2, therefore, are extinguished. When this occurs the condenser of stabilization device 16 is discharged through the resistor in parallel therewith until diodes T1 and T2 again fire.

The foregoing cycle of operations is repeated until the voltage of condenser C1 has been reduced to a value insufiicient to fire tubes T1 and T2 and the voltage of condenser Cl is now stabilized to a value in the order of a few millivolts below the breakdown voltage of diodes T1 and T2.

Switch 14 is now closed thereby further lowering the voltage of condenser C1 by a few additional millivolts as condenser C2 is charged therefrom.

At the completion of the arming time and after the voltage of condenser C1 has been stabilized and switch 14 has been closed, switch 18 is disengaged from its contact 19 and brought into engagement with contact 21 thereby connecting the electric primer 17 into the firing circuit in parallel with the stabilization device and without disconnecting the stabilization device from the firing condenser. The voltage of condenser C1, it will be noted, has been additionally reduced by the charging of condenser C2 therefrom sufliciently to prevent premature operation of diodes T1-T2 as switch 18 is operated into engagement with contact 21 thereof and the voltage across diodes T1-T2 is less by a few millivolts than the voltage required to fire the tubes.

As a firing signal is applied to condenser 22 and thence by conductor to the firing circuit, the delicate voltage balance of tubes T1T2 is destroyed and one of these tubes fires immediately causing firing of the second tube. When this occurs the discharge current from condenser C1 flows through primer 17 causing the fuze to operate and set off the main explosive charge.

On FIG. 2 is shown a stabilized RC circuit arrangement generally similar to the arrangement of FIG. 1 to the extent that the detonator is fired by the discharge current of a storage condenser when the voltage of the condenser has been raised sufliciently to break down the impedance of a diode tube included in the firing circuit in series with a vibrationally operated diode to which a previously stabilized voltage has been continuously applied. As in the circuit arrangement of FIG. 1 switching between the electrical primer and the stabilization device is avoided. The circuit of FIG. 2 comprises a pair of terminals 23 and 24 connected to a source of DC. voltage such as the battery 25 illustrated, the terminal 24 preferably being grounded. Terminal 23 is connected by conductor 26 4 to diode T3, condenser C1 and the wipers A and B of switch S respectively. The other terminal of diode T3 is connected by resistance R to grounded conductor 27 and the other terminal of condenser C1 is likewise connected to conductor 27.

The wipers A and B of switch S, it will be noted, are adapted to be moved synchronously across contacts 1, 2 and 3 of their respective wiper banks as the fuze receives an impact. Contacts 2 and 3 of wiper A are connected together and to a high resistance R1 from whence the circuit is continued by conductor 28 to one terminal each of diode T2 and storage condenser C4. Contact 2 of switch wiper B is connected by conductor 29 to one terminal of stabilizing condenser C2, stabilizing device 16 and to resistor R3. Resistor R3 is connected to condenser C3 from whence the circuit is continued by way of conductor 27 to ground. The other terminal of condenser C2 is likewise grounded. The opposite terminal of stabilizing device 16 is connected by conductor 31 to the other terminal of diode T2 and stabilizing diode T4, the other terminal of diode T4 being grounded by conductor 27. Diode T4 isof the type employing a vibrational element whereby the capacity of the tube is continuously varied while the element vibrates. An electroresponsive detonator 17 is grounded'at one terminal thereof to conductor 27 and connected by the other terminal to condenser C4.

The operation of the circuit of FIG. 2 will now be described. Let it be assumed, by way of example, that the switch S is in the position shown on the drawing with the Wipers A and B thereof in engagement with their contacts 1 and that the battery 25 is connected across the terminals 23 and 24. Condenser C1 is now charged to the potential of battery 25. This potential is in excess of the breakdown potential of diode T3 and diode T3 therefore ignites and upon disconnection of battery 25 from terminals 23 and 24 condenser C1 discharges through diode T3 by way of resistance R thereby lowering the potential of condenser C1 until the voltage drop across diode T3 is insufiicient to maintain diode T3 activated. Where this occurs diode T3 is extinguished leaving a predetermined potential at the terminals of storage condenser C1.

Upon impact, switch S operates. As wiper A of switch .5 moves into engagement with its contact 2 a circuit is closed through high resistance R1 to slowly charge condenser C4. This charging circuit for condenser C4 is maintained as the switch S moves into its final position 3 by reason of the interconnection between contacts 2 and 3 associated with wiper arm A. As wiper arm B of switch S engages its contact 2 condenser C1 is momentarily connected in parallel with condenser C2 thereby charging the condenser C2 to a value of voltage equal to the voltage on C1 and as the switch moves into position 3 this charging circuit for condenser C2 is interrupted. Condenser C3, it will be noted, is connected in parallel with condenser C2 by way of resistance R3 and condenser C2, therefore, is discharged slightly through this resistance until the potential thereof has been brought to equality with the potential of condenser C3. Condenser C3 is relatively small with respect to condenser C2 whereby the drop in voltage of condenser C2 caused by charging condenser C3 is of a low order.

The diode T4, it will be recalled, is of the vibrational type and one element thereof begins to vibrate as impact is received. The voltage on condenser C2 is sufficient to set the stabilizing circuit comprising the stabilization device 16 into operation and this circuit operates to reduce the voltage of condenser C2 to a value a few millivolts less than the breakdown voltage of diode T4, the time of such stabilization being in excess of the period of vibration of the vibrational element of tube T4 by a predetermined period of time such, for example, as 30 seconds. The values of condensers C2, C3 and resistance R3 are such that condenser C2 continues to discharge at a low rate and at a time constant in excess of theidurationof the stabilization operation-by approximately seconds whereby the voltage of condenser C2is reduced a few millivolts additionally below thevalue of thebreakdown voltage of diode T1.

Condenser C4 during this period of tirnehas been slowly charging through resistance R1 by way. of contact 3 and wiper A of switch S to the source of voltage at condenser Cl. When the voltage has been builtup on condenser C4 sufiiciently to fire diodes T2 and T4 in series by an increase in the potential of the condenser plates of C4 of a few millivolts, the breakdown potential of diode T3, condenser C4 discharges through the electric primer 17 causing the detonator to function. From the foregoing it should be noted that the breakdown voltage of diode T2 is greatly in excess of the breakdown voltage of diode T1 and that the sustained voltage of diode T3 added to the voltage drop through resistance R equals the voltage on condenser 01 and that the final voltage on condenser C4 just prior to explosion is less than thev. breakdown voltage of diodes T2 and T1. The final voltage of condenser C4, however, is greater than the breakdown voltage of diode T2 added to the extinguishingvoltage of diode T1.

The foregoing circuit arrangement suffers a loss in sensitivity with time as the voltage of condenser C2 .decreases due to leakage and finally results in selfldestruction.

The arrangement of FIG. 3 is generally similar tothe circuit arrangement of FIG. 2 but differs therefrom in,

respect to the manner in which the fuze is fired, the firing of the fuze being accomplished from a lowvoltage impulse source in a manner similar to the circuit of FIG. 1 or, in the event that this impulse is not received within in a predetermined period of time, the circuit is selfdestructive when the charge on condenser C4 thereof has reached a predetermined value.

The operation of the circuit of FIG. 3 will now be described. The circuit is provided with three terminals 32,

33 and a grounded terminal 34. An impact responsive;

device comprising a pair of synchronously operated switches S1 and S2 having their wipers connected to terminals 32 and 33 respectively is also. provided. Each of the wipers is provided with three contacts 1, 2 and 3 to be engaged in successive order as the switches operate.

A fixed potential is applied between terminals 33and 34 and a different selected potential between terminals 32 and 34. The operation of switches S1 and S2 upon impact causes condenser C2 to be charged to the potential applied to terminals 33-34 and the operation of switch S1 causes condenser C4 to be charged through resistor R2 at a slow rate of charge. As wiper of switch S2 moves out of engagement with contact 2 thereof the charging circuit of condenser C2 is interrupted and diodes Ti and T2 function to stabilize the voltage of condenser C2 by reason of the stabilization device 16 connected therebetween until the voltage of C2 is slightly less than the breakdown voltage of diodes T1-T2. When this occurs the voltage of condenser C2 is additionally reduced by a few millivolts until the voltage of condenser C3 has been brought to equality therewith. When this has been achieved switch 38 operates to conduct the electroresponsive detonator 17 to the firing condenser C4 in a manner similar to the operation of switch 18 of FIG. 1.

When the voltage of condenser C4 has been raised sufiicientiy to equal the value of breakdown voltage of diode T3 in series with the diodes T1 and T2, diode T3 fires thereby causing diodes T1 and T2 to discharge and fire the detonator 17. The self-destruction of the circuit in the manner just described will occur at predetermined intervals of time in accordance with the selected value of voltage supplied to terminal 32.

When employed with a proximity fuze, the circuit is fired by a small voltage signal in the order of a few 37 wine conductorinterconnectin tubes "TIand Obviously many modificationsfind variatioiis of the 1 present invention are scanners thelig ht oftlie above teachings, It is therefore' to be understood thatwithin Letters Paten't of the'United Statesis:

' 1.1An electrical fuze forv an ordnance device comprising a pair of .input terminals for connection to a source of voltage, a normally op en switch connected to oneiof said (terminals,v a storage condenser connected to one elementof saidswitch'and t the ther terminn whereby ,the condenser is charged rto the potential-of said voltage source as the switch is momentarily closed,'a"pair of serially connected diodes, a high impedancevoltagefstabilization device, a circuit/including said diodes and stabilization device connected in senes acros's the terminals of said condenser, the breakdown voltageof said serially connected 'diodesi'being less than the voltageof said condenser as in itially charged, an electrorespons'ive detonator having one terminalthereof connected in said circuit intermediate said stabilization device and the condenser, means connected to the other terminal of said electroresponsivedevice for switching the electroresponsive detonator in parallel with the voltage stabilization device when the voltage of said diode has been stabilized, and a firing. conductor connected in said circuit intermediate said diodes for firing thediodes in response to a weak impulse supplied thereto whereby the detonator is actuated by discharge current from said condenser.

2. A claim according to claim I further characterized by a second condenser of small capacity relative to the firstnamed condenser, and means for connecting said condensers in parallel when the'voltage of the first named condenser. has been stabilized thereby to 'e'fiebt a small incrernental reduction in'thevoltageof said first named condenser. i i

'3, A claim according to claim 1 in which theelectroresponsive detonator is; initially short circuited by said switching means.

. 4 .In an electrical f uze for an ordnance device, in combination, pair of terminalmlmeans f or applying at will a predetermined voltage to said lterr'ninals, "a storage condenser connected across said terminals; {and adapted to be charged to the potential of 'said'voltage'applying means, a gas filled tube having a high resistance element in series therewith connected across said terminals the.

voltage of said condenser being initially sufiiciently high to fire said tube whereby the voltage of said condenser is reduced to a predetermined value after the condenser has been disconnected from said voltage source by discharge current through said tube until the tube is extinguished, an impact switch having a pair of wipers conneoted to one of said terminals and movable'from an initial position to a final position as an impact is received, a second condenser connected to a contact of said switch and adapted to be charged to the voltage of said storage condenser during movement of the switch wipers from said initial to the final position, a high resistance element connected to another contact of said switch whereby the element is in electrical connection with said storage condenser when the switch is in said final position, a pair of diodes interconnecting the other terminal of vsaid resistance with said condensers, a high impedance stabilization device interconnecting said second condenser with a terminal of each of said diodes, a firing condenser connected to said other terminal of said high resistance, an 'electro-responsive detonator connected to the other terminal of said firing condenser, and a firing circuit including said firing condenser and detonator connected in parallel with said diodes for actuating the detonator when the voltage of said firing condenser has increased to the breakdown voltage of said pair of serially connected diodes. 5

5. A claim according to claim 4 but further characterized by a condenser of small capacity relative to said second condenser and having a high resistance in series therewith connected across said second condenser to reduce the voltage of the second condenser by a fractional portion of a volt after the voltage of the second condenser has been stabilized.

6. In a firing circuit for a fuze, the combination of a pair of serially connected diodes, a storage condenser connected to one of said diodes, means for momentarily charging said condenser to a potential in excess of the breakdown potential of said one diode, a stabilization device interconnecting the other terminal of said condenser with the other terminal of said one diode whereby the condenser is discharged by small increments corresponding in number to the discharge cycles of said one diode until the voltage thereof is insufficient to cause an additional discharge of the diode, an electroresponsive detonator, a second storage condenser connected in series with the detonator and said pair of diodes, means including a high resistance element for slowly charging said second storage condenser to a potential sufficient to fire said pair of diodes whereby the detonator is actuated by discharge current from second storage condenser.

7. A claim according to claim 16 in which said one of the diodes comprises a vibrational element adapted to reduce the impedance thereof as the element vibrates in response to an impact.

8. A claim according to claim 7 in which means are provided for additionally reducing the voltage across said first named storage condenser by a fractional portion of the volt after the voltage of the first named storage condenser has been stabilized.

9. A claim according to claim 8 in which the stabilized voltage of said first named condenser is slightly less than the breakdown voltage of said vibrational diode after the vibrational element thereof has ceased vibrating.

10. An electrical proximity fuze of the character disclosed having a grounded terminal, a second terminal for connection to a predetermined voltage and a third terminal for connection to a different voltage, an impact switch having a pair of wipers connected respectively to said second and third terminals and movable in unison from an initial position to a final position in response to an impact, a storage condenser connected to a contact of said switch and to said grounded terminal in such manner that the storage condenser is charged by the potential at said second terminal during movement of the switch toward said final position and thereafter disconnected from said second terminal as the switch moves into the final position, a pair of serially connected diodes, one terminal of one of said diodes being connected to said grounded terminal, means including a stabilization device connecting said diodes to the terminals of said storage condenser, the breakdown potential of said diodes being less than said predetermined voltage whereby the voltage of the storage condenser is reduced and stabilized to a value just below the breakdown potential of said pair of diodes, a firing conductor connected to one terminal of each of said pair of diodes, a third diode having one terminal thereof connected to one terminal of one of said pair of diodes, means including a second stabilization device and a high resistance element in series therewith interconnecting the other terminal of said third diode and a contact of said switch in such manner that the third diode is operatively connected to said difierent voltage as the switch moves into said final position, a firing condenser having a resistance element in series therewith connected serially with all of said diodes and adapted to be charged at a slow rate by said difi'erent voltage until the voltage thereof is suflicient to fire said third diode, an electroresponsive detonator, means for connecting the detonator in parallel with said resistance element when the voltage of said pair of diodes has been stabilized whereby the detonator may be fired by discharge current from said storage condenser selectively in response to a firing pulse of a small fractional part of a volt applied to said firing conductor or to the firing of said third diode when the voltage of the firing condenser has been brought to equality with the breakdown voltage thereof if the firing pulse is not received.

11. A claim according to claim 10 in which means including a small condenser and a high resistance serially connected across the terminals of said storage condenser are employed to reduce by a small fractional part of a volt the voltage of the storage condenser after the voltage thereof has been stabilized.

References Cited in the file of this patent UNITED STATES PATENTS 2,545,474 Kurland et al. Mar. 20, 1951 

